Telephone system



March 19, 1929. M. LANGER TELEPHONE SYSTEM Filed April 50,1926

Patented Mat 19, u1929.

UNITED lSTATES Pa'rENr OFFICE.-

MAX LANGER', .oF BERLIN-Haamsnonr, GERMANY, AssreNoR To lSIEMENS a HALsxE AKTIENGESELLSCHAFT, WERNERWERK, oF sIEMENssTAnT, NEAR BERLIN, GER- MANY.

TELEPHONE SYSTEM.

Application led April 30, 1926, Serial No. 105,648,` and in Germany July- 11, 1925.

The invention relates vto vtelephone systems in which connections are set up between in` coming and outgoing lines. When calls are set up in such systems, the

whole traffic may be disturbed if more than two lines are interconnected, thus effecting the so called double connections. AThese faults are especially liable to occur, for instance, at operators? positions, over which 4connections are set up between incoming and outgoing lines over cordless routes, for examples, b

merely pressing akey. The object/of the invention is to avoid such faults by absolutely preventing double connections, this being achieved by providing the incoming and voutgoing lines with testing devices, which prevent the'connecting up of one or more incoming or .outgoing lines to an existing connection. l

'As an example of the invention, the drawing shows acircuit for selectively setting up connections between three incoming and three outgoing lines. For example if the incoming line 2 is'to lie-connected to the outgoing line 1, the operator lactua-tes av key, thereby switching over its contacts 15e-4P. At contact 3 of this key, thefollowing circuit is established for the test relay P1: earth, windings I and II of P1, lead c1, contact 3S,`resistance W1, bat.- tery, earth. At/the contact 511, the relay. P1 short circuits its high resistance winding I,

thereby in known manner marking the incomingA line 2 engaged. t the contacts 6111 l 'and 711 the outgoing line 1-y is connected over the leads a1 and b1 to the contacts l and 2' of the connecting key. ,The contact LJcloses the following circuit for the test relay Q1 of the incoming line 2: earth, windings I and II of relay Q1, contact 41, leadl'al1, resistance W1, battery, earth.v At its contactq1 the relay Q1 short-circuits' its high resistance winding I,

thus marking'the outgoing linel engaged.

' 2 is switche'dthroughover the contacts 1a and 2S and the leads a1 and b1 to the outgolng line-1.

' If the" connecting operator', by'switching.`

1 over the contacts 11W-1411, attempts to conneet the outgoing line 3 tothe connection ex- At the 'contacts 911 and 10111 the incoming line isting vbetween the incoming line 2 and the of the energized test relay P1. The` relay P3 now prevents the switching through of the outgoing line 3, because its contacts 15"*1 andv 16p3 are not closed. The busy signal can' now be given to the operator in any desired manner, whereupon she returns the` contacts 11n- 1411 to their normal-position.

It the operator attempts to connect an incoming line, for example the incoming line 1, to the existing connection between the incom ing line 2 and the outgoing line 1, and for this j purpose presses the key whereby the contacts ,17--2012 are closed, the test relay Q2 of the lines are set up and the connecting up of some other incoming'or outgoing line to the connection set up is prevented. Hence there is no need-to describe these operations, as the method ofsetting up calls othenthan those de-4 scribed can be' directly ascertained from the drawing.

What is claimed is:

l.V In a telephone system, a manual switchboard, a plurality'ol incoming trunks, a plu'- rality of nutgoing trunks, keys at said switchboard for connecting any one of said incoming trunks to any one of said outgoingA trunks, and means automatically operativer'esponsive to theestablishment of suchf a connection by the operation of one of said keys for preventin the connection of any other incoming trun to the outgoing trunk in use and for preventing the'inc'oming trunk in use from being connected to any other outgoing trunk by the operation ofv any one `of the other of said keys.`

2. In a telephone system,.a manual switchboard,' a plurality of 'incoming trunks, a plu-A rality `of. outgoing trunks, separate keys at. said switchboard forconnecting any one of saidincoming trunks to any one of said outgoing trunks, means operative responsive to the actuation of one of sadkeys, thereby connecting a certain outgoingtialnktv a ce1'- tain incoming trunk, f or'preventing the connection of any other incoming trunk toV the connected outgoing trunk and for preventing the connected incoming -trunk :trom 4being connected to an c other outgoing trunk upon the actuation o any one of the other keys.

3. ln a telephone' system, a manual switchnsaid keys Vfrom connecting any other incom-v ing or outgoing trunk to either ot the two trunks connected by the actuation of said one of said keys. l

4. In a telephone system, a manual switchboard, a plurality of incoming trunks, a plurality of outgoing trunks, keys at saidswitchboard tor connecting anyone ot said incoming trunks to any one otsaid outgoing-trunks,

and separate means individual to each incoming trunk, each separate means being operative when the associated incoming trunk is connectedto an outgoing trunk by the actuation ot one otsaid keys, :for preventing any other incoming trunk from being connectedV to said outgoing trunk by the actuation of any one of the other of said keys.

5. In a telephone system, a manual switch-A board, a plurality of incoming trunks, a plurality-of outgoing trunks, keys at said switchboard tor connecting any one of said incoming trunks to any one ot said outgoing trunks, separatel means individual to each incoming trunk, each separate means being operative when the associated incomin trunk is connected to an outgoing ltrunk, y the actuation of one of said keys, for preventing any other incoming trunk from being connected to said outgoing trunk by the actuation of any one ot the other of said keys, and separate means individual to each outgoing trunk, each separate means being operative when the associated outgoing trunk is connected to an incoming trunk by the actuation ot one of said keys, for preventing any I other outgoing trunk from being connected to said incoming trunk by the actuation' ot' any one of the other of said keys.

6. In a telephone system, a manual switchboard, a plurality of incoming trunks, .a pluV rality of outgoing trunks, keys at said switchboard for connecting each of said incoming trunks to a di'erent outgoing trunk at the same time, means for preventing the simul.

taneous connection of two incoming trunks to the same outgoing trunk by the actuation of any two of said keys, and means for preventing the simultaneous connection of two outgoing trunks to the same incoming trunk by the actuation of any two of-said keys.

7. In a telephone system, a manual'switchboard, a plurality of trunks, a plurality of lines, keys at said switchboard for connect ing any trunk with any line, there being as many separate keys associatedwith eachtrunk as there are'lines, a 'test relay individual to each trunk, a test conductor lindividual to each line, normally open contact-sf in each trunk controlled bythe associated test relay, means for operating the test relay of ,a trunk when said trunk is connected to a line by the operation ofthe Corresponding key, and means controlled by said test relay I for placing a guarding potential on the test Aconductor of said line orpreventing the operation of the test relay of a second trunk when the key for connecting said second so trunk to said lineisoperated.

8. 1n a telephone system, a manual switcli board, a plurality of trunks, a pluralityot' lines, keys 4said switchboard for connecting any trunk with any line, there being as many separate keys associated with each trunk as l there are lines, a test relay and a test -con'- ductor individual to each line, a test relay and a test conductor individual to each trunk,

normally open contacts in each trunk and in each line controlled by the associated testl relays, means for operating the test relay of a trunk and the test relay ot a line when said trunk is connected to said line by the actuation ot the corresponding key, means controlled by the actuated trunk test relay forl I i placing a guarding potential on the test conductorof the connected line for preventing Athe operation of the test relay ot a second trunk when the key for connecting such sec-- ond trunk to said line is actuated, and means 10c' 'controlled by the actuated line test relay for placing a guarding potential en the test conductor of the connected trunk for preventing the operation of the test relay ot a second line when the key tor connecting such second line to the connected trunk is actuated.

9. In 'a telephone system, incoming trunks, outgoing trunks, a multiple tor each trunk normally disconnected from the trunk, keys tor connecting the multiple ot any incoming 11a trunk .with the multiple of any outgoing` trunk, a test relay for each incoming trunk for connecting the trunk to its multiple, a.

,test relay for each outgoing trunk for connecting the trunk toits multiple, and circuit connections such that when any one key is` operated to connect the multiple of'a certain incoming trunk with the multiple of a cer tain outgoing trunk, the test relay ot that certain incoming trunk and the test relay ot 1g@ that lcertain outgoing trunk are operated.

10. In a telephone system, incoming trunks, outgoing trunks, a multiple for each trunk normally disconnected from the trunk, keys lfor connecting the multiple of any incomingv trunk with the multiple of any outgoing trunk, a test relay for .each incoming trunk.

-for connecting the trunk to its mu1tiple,a test relay for each outgoing trunk tor connecting the trunk to its multiple, circuit connections such that when any one key is operated to connect the multiple of a certain incoming trunk with the multiple of a certain outgoing trunk, the test relay of that certain incoming connects the multiple of the connected incom-l ing trunk with the multiple of the. said any other outgoing trunk. 1 11. In a telephone system, incoming trunks,

; outgoing trunks, a multiple for each trunk normally disconnected from the trunk, keys for connecting the multiple of any incoming trunk with the multiple of any outgoing trunk, a test relaypfor each incoming trunk for connecting the trunk to its multiple, a test relay for each outgoing trunk for connecting the trunk to its multiple, circuit connections such that when any one key isoperated to connect the multiple of a certain incoming trunk with the multiple of a certain outgoing trunk7 the'test relay of that certain incoming trunk and the test relay of that certain outgoing trunk are operated, means controlled by the operated test relay of the connected incoming trunk for preventing the operation of the test relay of any other incoming trunk by the operation of the key Which connects the multiple of the connected outgoing trunk With the multiple of the said any other incoming trunk, and means controlled by the 4operatedtest relay of the connected outgoing trunk for preventing 'the operation o't' the test relay of any other outgoing trunk by the operation of the key which connects the multiple of the connected incoming trunk with the multiple of the said any other outgoing trunk. a

In Witness whereof, .I hereunto subscribe my name' this 8th day of April, A.. D. 1926.

MAX LANGER. 

